Cell cryopreservation is a technique for storing cells in a low-temperature environment to reduce cell metabolism and achieve long-term storage. The basic principle of cell cryopreservation is slow freezing, which is because when cells are cold below 0°C organelles become dehydrated, the concentration of soluble substances in cells increases, and ice crystals are formed in cells, while slow freezing allows cells to be gradually dehydrated and large ice crystals are not produced in cells, because large crystals can easily cause damage and rupture of cell membranes and organelles.

At present, the commonly used technique for cell cryopreservation is liquid nitrogen cryopreservation, which mainly uses the slow freezing method with the appropriate amount of protective agent to freeze cells.

DMSO (dimethyl sulfoxide) is a commonly used cryoprotectant in cell cryopreservation. In the 1950s, British scientists discovered that DMSO can be used as an antifreeze agent when preserving cells at deep low temperatures (-200 degrees Celsius). It is an osmotic protectant that can quickly penetrate cells, improve the permeability of cell membranes to water, lower the freezing point, delay the freezing process, and enable intracellular water to permeate out of cells before freezing, forming ice crystals outside the cells and reducing intracellular ice crystals, thus reducing the damage to cells from ice crystals.

DMSO is a widely used cryoprotectant for cells.